Catalyst and process for the fluid-bed oxychlorination of ethylene to EDC

ABSTRACT

A fluidizable catalyst composition is provided containing about 2% to about 8% by weight of copper (about 4% to about 17% by weight of copper salt), from about 1.0% to about 10% by weight of a rare earth metal salt(s), preferably the chloride salt(s), and from about 0.25% to about 2.3% by weight of an alkali metal salt(s), preferably the chloride salt(s), all weight percents based upon the total weight of the catalyst composition. The metals are codeposited on a fluidizable, high surface area alumina support. The weight of the alkali metal employed is not over 2.5% by weight (as the chloride) and the weight ratio of the rare earth metal salt(s) to the alkali metal salt(s) must be at least 1:1. Such catalyst compositions are extremely useful as fluid bed catalysts in the vapor phase oxychlorination reaction of ethylene, oxygen and hydrogen chloride to produce 1,2-dichloroethane (EDC). The use of the catalysts results in improved, high percent ethylene efficiencies and high percent HCl conversions, and avoids operating problems caused by stickiness of the catalyst in the fluid bed. A combination of copper chloride, potassium chloride and one or more of the rare earth chlorides on a fluidizable gamma alumina support, produces an excellent catalyst for a fluid bed ethylene oxychlorination process.

This a division of application Ser. No. 898,566 now U.S. Pat. No.4,740,642, filed Aug. 21, 1986.

BACKGROUND OF THE INVENTION AND REFERENCES TO THE PRIOR ART

This invention pertains to fluid bed, catalytic oxychlorination ofethylene to produce 1,2 dichloroethane, commonly called ethylenedichloride (EDC), and relates specifically to improved copper chloridecatalysts and their use in an ethylene oxychlorination reaction.

The production of chlorinated hydrocarbons by oxychlorination is knownto the art. For example, a well known process for oxychlorination ofethylene to produce EDC, practiced in many commercial installationsthroughout the world, involves the vapor phase reaction, over afluidized catalyst bed, of a mixture of ethylene, hydrogen chloride(HCl) and oxygen or an oxygen containing gas (e.g., air) in the mannerand under the conditions described in U.S. Pat. No. 3,488,398 granted toHarpring et al.

A typical catalyst used in fluid bed oxychlorination reactions comprisesabout 4% to 17% by weight of a copper compound. Typically, the coppercompound is cupric chloride, as the active catalytic ingredient,deposited on particles of a fluidizable support, such as silica,kieselguhr, clay, fuller's earth, or alumina. The support should bereadily fluidizable without excessive catalyst loss from the reactionzone, and have proper bulk density, resistance to attrition and particlesize and distribution to be useful in the process. In prior artoxychlorintion processes most closely aligned to the present invention,an alumina support is employed which may be gamma alumina, alphaalumina, the so-called microgel aluminas or other forms of "activated"alumina. The standard, fluid bed alumina-based oxychlorination catalystscan be improved upon in significant respects.

First, it is desirable for the oxychlorination catalyst to effect thehighest possible yield of EDC based on ethylene (i.e., for the ethyleneto be more completely converted to EDC, with less ethylene being reactedto carbon oxides or higher chlorinated materials). In the high volumebusiness of manufacturing EDC, small increases in the efficiency ofethylene conversion to EDC are very valuable. For example, in a onebillion pound per year EDC oxychlorination plant, an ethylene efficiencyincrease of only 1% can result in a savings of from about 0.4 to about1.0 million dollars annually. Further, increased ethylene efficiencyreduces the potential of release of hydrocarbons and chlorinatedhydrocarbons to the environment.

Second, it is becoming much more desirable for economic andenvironmental reasons, for the oxychlorination catalyst to also effect ahigh conversion of the hydrogen chloride (HCl) used in the reaction.Problems can arise when a higher than theoretical molar ratio of HCl toethylene is used in an attempt to achieve higher ethylene conversions toEDC. Unconverted HCl must be neutralized using, for example, a causticsolution, and the resulting salt must be disposed. Also, higher levelsof HCl in the process can lead to higher HCl "break through" downstreamof the reactor which can cause corrosion problems. Hence, a modernoxychlorination process will attempt to operate at an HCl to ethylenemolar ratio as close to the theoretical level of two-to-one (2:1) aspossible in conjunction with high HCl conversion. In such an operation,a combination of high HCL conversion and high ethylene efficiency ismost desirable.

Lastly, typical cupric chloride on alumina, fluid bed catalysts exhibita strong tendency to develop "stickiness" during the oxychlorinationreaction at HCl to ethylene molar feed ratios of about 1.9 to 2.0.Catalyst stickiness, which is basically agglomeration of catalystparticles, is a critical barrier to achieving optimum ethylene and HClfeedstock efficiencies in a fluid bed oxychlorination process. Highethylene efficiency from an oxychlorination catalyst requires operationwith an HCl/ethylene molar feed ratio approaching the stoichiometricvalue of 2.0. However, as the HCl/ethylene feed ratio is increased aboveabout 1.9 in a commercial process, standard fluid bed oxychlorinationcatalysts become progressively more sticky. With increased catalyststickiness, heat transfer characteristics of the fluid bed worsen, hotspots develop within the catalyst bed, feedstock conversions and yieldsdecline, and, in extreme cases, the bed actually collapses and slumpscausing vapor passages through the bed. Therefore, a high performanceoxychlorination catalyst requires operation with HCl/ethylene feedratios approaching 2.0, excellent fluidization, and high conversions,yields, and efficiencies. This problem of catalyst stickiness and adevice and means for its partial control are described in U.S. Pat. No.4,226,798 issued to Cowfer et al. A method of controlling stickiness instandard oxychlorination catalysts is also described in U.S. Pat. No.4,339,620 also issued to Cowfer et al. Although these devices andmethods are helpful, it is more practical and efficient to employ anoxychlorination catalyst which does not develop stickiness during thereaction.

By way of further background, it has been proposed in the prior art toconduct oxychlorination reactions using a fluid bed catalyst in whichthe catalyst contains not only copper chloride but other metal compoundssuch as chlorides and oxides of alkali metals, alkaline earth metals,transition metals, and/or rare earth metals. For example, U.S. Pat. No.3,427,359 describes a catalyst composition useful for fluid-bedoxychlorination of hydrocarbons consisting of copper chloride, an alkalimetal chloride and/or a rare earth metal chloride supported on an alphaalumina having a surface area no greater than 10 m² /g. Likewise, U.S.Pat. Nos. 3,657,367; 3,914,328; 3,992,463; 4,069,170; 4,124,534 and4,284,833 and Canadian Pat. No. 701,913 all teach the use of metalchlorides deposited with copper chloride on low surface area (alumina)supports. However, these low surface area support catalysts are notuseful in the fluid bed ethylene oxychlorination process of the presentinvention because the ethylene efficiency is very low.

There are also patents which disclose the use of alkali metals, alkalineearth metals, and/or rare earth metals along with copper chloride onhigh surface area supports. For example, U.S. Pat. Nos. 3,468,968;3,642,921; and 4,123,389 all broadly disclose the use of a catalyst ofcopper chloride and alkali metals such as KCl, and/or rare earth metalssuch as cerium, praeseodymium, neodymium, and lanthamum. Whereas thesecatalysts are closer in composition to those of the present invention,optimization in composition and improvements in performance can still beobtained. All of these references are deficient in that none teach orsuggest the optimization of the ratio of the types of metals used toeach other in affecting catalyst performance.

Lastly, other patents in the prior art do teach or suggest that bettercatalysts are obtained if the added metals are employed in a certainweight or molar ratio of added metal(s) to the copper present. Forexample, U.S. Pat. Nos. 3,205,280; 3,308,189; 3,308,197; 3,527,819;3,769,362; 3,862,996; 4,046,821; 4,123,467; 4,206,180; 4,239,527;4,329,527; 4,451,683 and 4,460,699 all broadly disclose that a certainweight or mole ratio of added metal to copper improves the catalyst.

From the above, it is readily seen that much effort has been put intodeveloping "optimum" catalysts for oxychlorination reactions. Of all theabove-referenced patents, it is worthwhile to note those patents mostclosely aligned with the catalyst and process of the present invention.U.S. Pat. No. 3,205,280 discloses a catalyst composition of an Al₂ O₃support (calcined at 900° C. which substantially lowers its surfacearea) having thereon an alkali metal such as potassium chloride, analkaline earth metal, a transition metal such as copper, and/or a rareearth metal such as didymium. The atomic ratio of alkali or alkalineearth metal to transition or rare earth metal is at least one-to-one tono more than seven-to-one. Preferably, the patent teaches an atomicratio of alkali metal to transition metal to rare earth metal of 4:1:1.A catalyst of KCl, DiCl₂, and CuCl₂ on alpha-Al₂ O₃ is shown in ExampleIV.

U.S. Pat. No. 3,308,197 broadly teaches a catalyst composition ofaluminum oxide containing Group Ia and/or IIa metals such as potassiumchloride and a Group IIIb metal such as ceric oxide, wherein the ratioof metal atoms from Groups Ia and IIa to Group IIIb is from 0.01 to 1.5: 1. A catalyst of CeO₂ and KOH on Vycor Raschig rings is disclosed inExample 6.

U.S. Pat. No. 3,527,819 broadly teaches a process for preparing tri-andtetrachloroethylene using a catalyst composition of copper chloride,potassium chloride, and neodymium chloride on a high surface area silicagel support. The atomic ratio of potassium to copper in the catalyst is0.6 to 1 : 3 to 1, and the atomic ratio of neodymium to copper is atleast 0.4 to 1. The patent's teaching is specific to neodymium chloride.However, comparative catalysts containing up to 2.5% by weight of rareearth metals are shown in Table 1.

U.S. Pat. No. 3,862,996 broadly teaches a process for preparing ethylenefrom ethane using a catalyst composition of an alumina supportcontaining copper halide and a rare earth metal halide, and optionallyan alkali metal halide such as KCl or LiCl. The weight ratio of rareearth metal halide to copper halide in the catalyst is greater thanone-to-one. A catalyst of CuCl₂, rare earth metal halide (cerium halideand didymium halide) and LiCl on an alumina support is shown in theExamples.

U.S. Pat. No. 4,046,821 broadly teaches a catalyst composition of a lowsurface area support containing a copper (non-halide) compound such asCuCO₃, a rare earth metal compound, and optionally an alkali metalcompound. The atomic ratio of rare earth metal to copper in the catalystis 4 to 0.1 to 1. Catalysts of CuCO₃, CeO₂ and KCl on a low surface areaalumina are shown.

Lastly, U.S. Pat. No. 4,451,683 broadly teaches a catalyst compositionof a copper compound such as CuCl₂, an alkali metal such as KCl, and arare earth metal such as CeCl₃ on a high surface area magnesium oxide -aluminum oxide support. The number of alkali metal ions in the catalystis less than 100 per 100 ions of copper. A catalyst of CuCl₂, KCl, andCeCl₃ on a high surface area MgO,Al₂ O₃,Na₂ O support is shown in Table3.

The deficiency in the above patents is that none of these patents teachor disclose the effect of the ratio of rare earth metal to alkali metalon catalyst stickiness and performance.

As a final prior art reference, U.S. Pat. No. 4,446,249, issued to J.Eden, one of the present inventors, discloses a method of obtaining animproved oxychlorination catalyst of cupric chloride on a gamma-aluminasupport, modified with one or more of an alkali metal, an alkaline earthmetal, and/or a rare earth metal wherein the critical feature of thepatent consists of "fixing" the modifying metal(s) to the support by acalcination step prior to deposition of the cupric chloride. Thepre-calcination of the modifying metal(s) to the support before addingthe copper makes the catalyst composition less prone to stickinessduring use. The catalysts of the present invention are distinguishedover this prior art in that, in the present invention, a fluidizable(non-sticky), high ethylene efficiency, high HCl conversion catalyst isobtained without the need of calcining the alkali metal and rare earthmetal to the support before depositing the cupric chloride.

SUMMARY OF THE INVENTION

The catalyst compositions of the invention are highly fluidizablecatalysts of a high surface area alumina support having thereon copperchloride, at least one alkali metal and at least one rare earth metal.The catalysts compositions are prepared by co-depositing the metals onthe high surface area alumina support without the need of firstcalcining the non-copper metals to the support, provided that the weightratio of rare earth metal salt(s) to alkali metal salt(s) is at least0.8:1. The use of the catalyst compositions of the invention in theoxychlorination of ethylene to EDC results in high percent ethyleneefficiency and percent HCl conversion without exhibiting catalyststickiness.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE depicts the performance of various catalyst compositions inan oxychlorination reaction in terms of high performance, which is acombination of high ethylene efficiency, high HCl conversion, and goodfluidization. All the catalysts shown in the drawing contained 10.6% byweight of the copper compound (cupric chloride) in addition to theindicated weight percents of the alkali metal salt (potassium chloride)and rare earth metal salt (cerium chloride). All oxychlorinationreactions were conducted at a molar ratio of ethylene to HCl to oxygenof 1:2:0.8, at a temperature of 225°±1° C., and a contact time (definedfor a settled bed) of 22±0.5 seconds.

The abscissa is weight percent of alkali metal salt (potassium chloride)contained on the catalyst composition. The ordinant is weight percent ofrare earth metal salt (cerium chloride) contained on the catalystcomposition. The envelope imposed on the graph represents the area ofhigh performance in which both high ethylene efficiency and high HClconversion along with good catalyst fluidization is obtained. Thecatalyst compositions of the invention fall into the high performancearea. Poor fluidization occurs when too high of a level of alkali metalsalt is used or the weight ratio of rare earth metal salt to alkalimetal salt is too low.

DETAILED DESCRIPTION OF THE INVENTION

The catalyst compositions of this invention employ high surface aluminasupport materials which are readily available. The alumina supportmaterial has a surface area in the range of about 80 to 200 m² /g, acompacted bulk density in the range of 0.9 to 1.1 grams per c.c., a porevolume in the range of 0.2 to 0.5 c.c. per gram and a particle sizedistribution such that about 70 to 95 weight percent of the particlesare below 80 microns in diameter, about 30 to 50 percent are below 45microns in diameter, and about 15 to 30 percent are below 30 microns indiameter, with no more than 5% of the particles larger than 200 micronsor more and no more than 10% of the particles smaller than 20 microns.Such alumina support materials are readily fluidizable, relativelystable, mechanically strong and resistant to attrition. Alumina supportsthat meet the above criteria are sold by Harshaw/Filtrol Partnership,Ketjen Catalysts, and other catalyst suppliers.

It is recognized that some alumina support materials may contain inaddition to aluminum oxide (Al₂ O₃) traces of other metals such as metaloxides like sodium oxide. These alumina supports are readily useable inthis invention.

The alkali metal employed in the present invention can be sodium,potassium, lithium, rubidium, or cesium, or a mixture of one or moresuch metals. The alkali metal is used in the form of a water solublesalt, and preferably is used in the form of an alkali metal chloride.However, other alkali metal salts that would convert to the chloridesalt during the oxychlorination process can also be used, such as thecarbonate salt or other halide salts like the bromide salts. The alkalimetal is used in the range from about 0.25% to about 2.3% by weight (asthe chloride) based on the total weight of the catalyst composition. Thepreferred alkali metals are potassium, lithium, and cesium. The mostpreferred alkali metal is potassium, and the preferred alkali metal saltis potassium chloride used at from about 0.5% to 2% by weight based onthe total weight of the catalyst.

The rare earth metal employed in the invention can be any of theelements listed as elements 57 through 71 of the Periodic Table.Examples of rare earth metals include lanthanum, cerium, praeseodymium,neodymium, or naturally occurring mixtures of one or more such metalssuch as didymium. The rare earth metal is used in the form of a watersoluble salt, and preferably is used in the form of a rare earth metalchloride. However, other rare earth metal salts which would convert tothe chloride during the oxychlorination process can also be used, suchas the carbonate salt or other halide salts like the bromide salt. Therare earth metal is used in the range from about 0.2% to about 15% byweight (as the chloride) based on the total weight of the catalystcomposition. The preferred rare earth metals are cerium, lanthanum,praeseodymium, and neodymium. The most preferred rare earth metal iscerium, and the preferred rare earth metal salt is cerium chloride usedat from about 1% to 10% by weight.

Addition of the metals onto the alumina support is accomplished byimpregnating the support with an aqueous solution of a water solublesalt of the metals along with a water soluble salt of the coppercompound and then drying the wetted support. The alkali metal and rareearth metal salts do not have to be calcined on the support prior todeposition of the copper compound to produce a fluidizable catalyst, aslong as the weight ratio of rare earth metal salt(s) to alkali metalsalt(s) is at least (as the chloride) 0.8:1 and the total amount ofalkali metal salt(s) in the alumina support is under 2.5% by weight.More preferredly, the weight ratio of rare earth metal salt(s) to alkalimetal salt(s) is from one-to-one (1:1) to about thirty-to-one (30:1),and even more preferably from about two-to-one (2:1) to about ten-to-one(10:1).

It was surprisingly discovered that only a particular range of loadingsof copper, alkali metals, and rare earth metals and only particularratios of rare earth metals to alkali metals would result in all of thehigh performance characteristics described above. Outside of theparticular loadings and ratios of the active metals, high performance isnot achieved either because the catalyst composition becomes stickyand/or lower percent ethylene efficiency and percent HCl conversion isobtained.

The copper compound is also used in the form of a water soluble salt,and preferably is used in the form of cupric chloride. However, othercopper salts that would convert to the chloride during theoxychlorination process can also be used, such as the carbonate salt orother halide salts like the bromide salt. The copper salt is depositedon the alumina support using the same techniques as described above. Theamount of copper deposited is based on the activity desired and thespecific fluidization characteristics of the support. The amount ofcopper employed is in the range from about 2% by weight to about 8% byweight as copper metal, from about 4% to about 17% by weight as thecopper salt, both based on the total weight of the catalyst composition.More preferredly, the copper salt is employed in the range from about 8%to about 12% by weight, and the most preferred copper salt is copperchloride. The final catalyst composition containing the alkali metal(s),rare earth metal(s) and copper compound is readily fluidizable. However,certain specific characteristics such as surface area and pore volume,for example, are, of course, modified by reason of the deposit of themetals. Hence, the catalyst compositions of this invention have a finalsurface area in the range of about 70 to about 160 M² /g, which is about10% to 30% lower than that of the alumina support before the deposit ofthe metals. The preferred range of surface area for the catalysts isabout 85 to about 125 m² /g.

Other metals can be present in the catalyst compositions of theinvention in relatively small amounts. For example, alkaline earthmetals and/or transition metals can be present in up to about 1% byweight total based on the total weight of the catalyst composition.Examples of such other metals are magnesium, barium, iron, and the like.

The catalyst compositions of this invention are readly prepared bywetting the alumina support material, as above described, with anaqueous solution of a salt(s) of the desired metals. The wetted aluminais then dried at about 80° C. to 110° C. to remove water. An amount ofthe metal salt is chosen so that the final catalyst contains from about0.25% to about 2.3% by weight of the incorporated alkali metal (as thechloride) and from about 0.2% to about 15% by weight of the rare earthmetal (as the chloride), both based on the total weight of the catalystcomposition. The metal salt used in the aqueous solution can be in theform of any water soluble salt such as previously described, like thechloride or carbonate salt of potassium, sodium, lithium, rubidium orcesium, or of lanthanum, cerium, praeseodymium, neodymium, and didymium(which is a mixture of rare earth metals which contains lanthanum andneodymium together with smaller amounts of praesodymium and samarium andeven smaller amounts of rare earth metals). The specific combination ofpotassium chloride with rare earth metals such as lanthamum,praeseodymium, neodymium, and particularly cerium chloride isparticularly desirable.

A critical feature of the catalyst compositions of this invention isthat, within the weight ranges of alkali metal and rare earth metalstated herein, the weight ratio of rare earth metal salt(s) to alkalimetal salt(s) must be at least 0.8:1 or higher or stickiness, hot spots,and caking occur with use of the catalyst. Whereas prior art processeshave advised many techniques to reduce stickiness, it was unexpectedlydiscovered that catalyst stickiness can be prevented by employing adefined weight level of alkali metal(s) and a defined weight ratio ofrare earth metal(s) to alkali metal(s).

The catalyst compositions of the invention are highly efficientcatalysts for the oxychlorination of ethylene to EDC. The reactionprocess temperatures vary from about 190° C. to about 250° C., and morepreferredly from about 220° C. to 240° C. Reaction pressures vary fromatmospheric to about 70 psig. Contact times in the fluid bed vary fromabout 10 seconds to about 50 seconds, and more preferably are from about20 to 35 seconds. The ratio of the ethylene, HCl, and oxygen reactants,based on the moles of HCl charged, range from about 1.0 to about 1.1moles of ethylene and about 0.5 to about 0.9 mole of oxygen per 2.0moles of HCl. As previously mentioned, modern oxychlorination processesattempt to operate as close as possible to the stoichiometric ratio of 2moles of HCl to 1 mole of ethylene.

When the novel catalyst compositions are used under commercialproduction conditions in the oxychlorination of ethylene to EDC at about230° C. with about a 30 second fluid bed contact time, the conversion ofethylene is 99% or above and the percent ethylene efficiency is aboveabout 96%. This efficiency compares with a normal commercial ethyleneefficiency of about 93 up to 95% obtained using conventional, knowncatalyst compositions. The percent conversion of HCl is also very highusing the catalysts of the present invention, exceeding 99% HClconversion. The catalyst compositions of this invention aresignificantly less "sticky" when used under commercial oxychlorinationreaction conditions. Accordingly, this invention provides, in additionto improved catalyst compositions, an improved fluid-bed ethylene to EDCoxychlorination process. Laboratory scale processes, operating underhigher control and more ideal conditions, yield even better results.

The specific Examples are set forth below to illustrate the unique andunexpected characteristics of the catalyst compositions of thisinvention, and are not intended to be limiting of the invention. TheExamples particularly point out the criticality of (1) using a highsurface area alumina support, (2) using a combination of copperchloride, rare earth metal(s) and alkali metal(s), and (3) employing thecorrect weights of copper chloride and alkali metal salt(s) and correctweight ratio of the rare earth metal salt(s) to alkali metal salt(s). Inall of the Examples, the fluid bed oxychlorinatin reaction is conductedusing a bench scale fluid bed reactor of either 2.2 cm. internaldiameter and 107 cm. height or 3.0 cm. internal diameter and 50 cm.height charged with 325 cc. or 250 cc., respectively, of the fluid bedcatalyst composition as described. The reactor volume, the amount andpacking of catalyst charged to the reactor and reactant flow rates alleffect the contact time between reactants and catalyst. The contacttimes were calculated based on a settled bed of catalyst, and weredetermined by dividing the settled bed volume by the volumetric flowrate of the feed gases at the reaction temperature and pressure. Thereactor is equipped with means for delivering gaseous ethylene, oxygen(as air) and HCl through the fluid bed reactor zone, means forcontrolling the quantities of reactants and reaction conditions, andmeans for measuring and ascertaining the composition of the effluentgases to determine the percent HCl conversion, percent yield of EDC, andpercent ethylene efficiency.

EXAMPLES

A series of experiments were performed to show the unique features ofthe catalyst compositions of the invention. In the experiments, thereactants ethylene, oxygen and hydrogen chloride, all in the gas phase,were fed to the reactor in a molar ratio of 1.0 mole of ethylene and 0.8moles of oxygen for each 2.0 moles of hydrogen chloride. Since it wasdifficult to achieve a flow rate that would result in an exacttheoretical level of HCl to ethylene of 2.0 to 1.0, and the percent HClconversion is somewhat dependent upon the HCl/ethylene ratio, it wasnecessary to correct the measured percent HCl conversion to adjust forany deviation from a theoretical ratio of 2 to 1. This was done usingthe following formula:

    X.sub.2 =1/2(X.sub.1 Y.sub.1)

where

X₂ is the corrected precent HCl conversion (corrected to an exactHCl/ethylene molar feed ratio of 2:1)

X₁ is the percent HCl conversion determined by analyzing and measuringall components from the exit stream

Y₁ is the HCl/ethylene molar feed ratio determined by analyzing andmeasuring all components from the exit stream.

In applying the above equation to correct the percent HCl conversionvalue, for any specific value of the HCl/ethylene molar feed ratiowithin the range of 1.96 to 2.04:1, the values of percent ethyleneefficiency and crude EDC purity are assumed to remain essentiallyconstant, so that it is predominantly the value of percent HClconversion which changes with the slight variations in HCl/ethylenemolar feed ratio.

The reactions were conducted at temperatures in the range of about 220°C. to about 230° C. by passing the reactants through the fluidizedcatalyst bed to form EDC. The catalysts used in the experiments eachcontained about 10% by weight of cupric chloride as the primarycatalytic metal. The fluidizable alumina support used was a gammaalumina having a surface area of 150 to 165 square meters per gram(m^(2/) g). All of the metals were deposited on the fluidizable aluminasuppport by thoroughly mixing the alumina support with an aqueoussolution of cupric chloride, the alkali metal chloride, and the rareearth metal chloride, followed by drying the wetted mass to fluidity byheating on a steam bath and/or in an oven at temperatures up to about275° C. for 4 to 8 hours. The fluidizable catalyst composition had asurface area lower than the starting alumina support by a factor ofabout 10 to 30 percent.

During the experiment being run (the duration of which was sufficient toassure as much stability in the fluid bed as possible, but was otherwiseinsignificant) the condition of the catalyst fluid bed in terms ofstickiness of the particles was observed and rated. The results of thesetests in terms of catalyst stickiness are also reported in the followingExamples.

COMPARATIVE EXAMPLE A

In a comparative experiment, a catalyst was prepared containing 10.6% byweight cupric chloride, 1% by weight of a rare earth metal (Lanthanumchloride) and 1% by weight of an alkali metal (Potassium chloride) on analpha-alumina support, which is a low surface area alumina as disclosedin many U.S. patents such as U.S. Pat. Nos. 3,427,359; 4,069,170; and4,124,534. The metals were codeposited onto the alumina support usingthe procedure previously described above. This Comparative catalystbasically differs from the catalyst compositions of the presentinvention in the type of alumina support employed. The Comparativecatalyst was used in an oxychlorination process under conditions asdescribed below with the following results. It is apparent from the datathat the use of an alpha-alumina support (low surface area support)results in a very low percent ethylene conversion and low percentethylene efficiency. Hence, the data shows that the present invention islimited to high surface area alumina supports.

                  TABLE A                                                         ______________________________________                                        Support: alpha alumina having a surface area of 32 m.sup.2 /g                 Metal Salts: KCl, LaCl.sub.2, CuCl.sub.2                                      Weight Percent of Metals (as chlorides): 1% K, 1% La, 10.6% Cu                Reactant Feed Ratios: C.sub.2 H.sub.4 /O.sub.2 /HCl = 1.0/0.8/2.0             ______________________________________                                                 Contact   Percent   Percent                                                                              Percent                                   Temperature                                                                            Time      Ethylene  Yield of                                                                             Ethylene                                  (°C.)                                                                           (Seconds) Conversion                                                                              EDC    Efficiency                                ______________________________________                                        225      20        25.8      98.9   25.5                                      ______________________________________                                    

COMPARATIVE EXAMPLE B

A series of experiments were conducted to demonstrate the effect oncatalyst performance of the combination of the alkali metal and the rareearth metal versus the use of either type of metal alone. In theseexperiments, the alkali metal employed was potassium as KCl, and therare earth metal employed was cerium as CeCl₃. The weight of cupricchloride in the catalyst is 10.6% by weight. The molar feed ratio was1.0 mole of ethylene to 0.8 mole of oxygen to 2.0 moles of HCl. Thepercent HCl conversion was measured and then corrected to adjust for anyHCl feed variation from a theoretical 2:1 ratio over ethylene. Thereactor design described in the specification was employed. A standardoxychlorination catalyst consisting of cupric chloride on a gammaalumina support was prepared and employed as a control. The followingdata was obtained. Catalyst stickiness was also observed and reported.

                                      TABLE B                                     __________________________________________________________________________    Weight %    Temperature                                                                          Contact                                                                              % Ethylene   HCl Conversion                                                                           % EDC                                                                              Fluidization           Catalyst                                                                           KCl                                                                              CeCl.sub.3                                                                        (°C.)                                                                         Time (Sec.)                                                                          Conversion                                                                          Efficiency                                                                           Actual                                                                            Corrected                                                                            Yield                                                                              of                     __________________________________________________________________________                                                           Catalyst               Control                                                                            none                                                                             none                                                                              225    21.0   99.9  93.8   94.7                                                                              95.4   93.9 Fluid                  1    0.7                                                                              none                                                                              225    21.0   99.0  97.3   98.2                                                                              97.6   98.3 Hot spot                           230    21.0   99.5  97.2   97.9                                                                              97.7   97.7 Hot Spot                           225    31.8   99.9  97.0   98.2                                                                              97.7   97.1 Hot Spot                           230    31.8   100.0 96.1   97.9                                                                              97.3   96.1 Hot Spots              2    1.1                                                                              none                                                                              225    21.7   99.1  96.8   96.4                                                                              97.2   97.7 Hot Spot                           230    21.7   99.5  96.4   97.7                                                                              97.0   96.8 Poor                               225    32.3   99.9  96.6   96.1                                                                              97.2   96.7 Poor                               230    32.3   100.0 97.3   96.2                                                                              97.7   97.3 Poor                   3    5.0                                                                              none                                                                              225           --    --     --  --     --   Severe                                                                        Stickiness             4    none                                                                             2.0 225    21.6    99.9 97.7   98.3                                                                              99.2   97.9 Fluid                              230    21.6   100.0 97.5   97.1                                                                              97.4   97.5 Fluid                              225    32.2   100.0 96.2   97.1                                                                              96.8   96.2 Fluid                              230    32.2   100.0 95.0   96.4                                                                              95.9   95.0 Fluid                  5    none                                                                             8.0 225    22.0   99.2  96.7   96.7                                                                              97.3   97.5 Fluid                              230    22.0   100.0 95.9   97.0                                                                              96.9   95.9 Fluid                              225    32.9   100.0 94.1   96.5                                                                              95.3   94.1 Fluid                              230    32.9   100.0 94.5   95.4                                                                              96.3   94.5 Fluid                  6    0.7                                                                              2.0 225    21.7   99.6  97.6   98.6                                                                              98.0   98.0 Fluid                              230    21.7   99.9  96.6   97.4                                                                              97.4   96.7 Fluid                              225    32.3   100.0 96.4   97.7                                                                              97.1   96.4 Fluid                              230    32.3   100.0 95.5   96.6                                                                              97.1   95.5 Fluid                  7    1.5                                                                              4.0 225    21.6   99.2  97.5   96.3                                                                              97.8   98.3 Fluid                              230    21.6   99.7  97.6   96.7                                                                              98.2   98.0 Fluid                              225    32.3   99.9  97.5   97.5                                                                              98.1   97.5 Fluid                              230    32.3   100.0 96.9   96.9                                                                              98.0   96.9 Fluid                  __________________________________________________________________________

The data shows that the use of a catalyst of cupric chloride and analkali metal alone (experiments 1 to 3) can yield higher % Ethyleneefficiency and higher %HCl conversion than the Control, but at adisadvantage of progressively worse fluidization in the catalyst bedwith higher alkali metal content. At a level of 5 percent by weight ofalkali metal (potassium chloride), the catalyst was so sticky that thereaction could not be run. Experiments 4 and 5 show that the use of acatalyst of cupric chloride and a rare earth metal alone can increase %Ethylene efficiency and %HCl conversion over that of the Control,without catalyst stickiness problems. However, percent ethyleneefficiency and percent HCl conversion significantly decrease withincreasing temperature and contact time. At conditions of commercialprocesses of about 230° C. and about 30 seconds contact time, lowerpercent ethylene efficiency (about 94% to 95%) and lower percent HClconversion (about 96% to 97%) are observed. Experiments 6 and 7 showthat high % Ethylene efficiency (about 96% to 97%) and high % HClconversion (about 97% to 98%) are achieved using the catalysts of thisinvention. These high efficiencies are obtained over a wide range ofoperating conditions without any fluidization problems.

COMPARATIVE EXAMPLE C

A series of experiments were conducted to demonstrate the effect oncatalyst performance of the weight of alkali metal in the catalyst andthe weight ratio of rare earth metal to alkali metal in the catalyst. Inthese experiments, the alkali metal employed was potassium as KCl, andthe rare earth metal employed was cerium as CeCl₃. The weight of cupricchloride in the catalyst is 10.6% by weight.

                                      TABLE C                                     __________________________________________________________________________                Weight Ratio of                                                                         Percent                                                                             Percent      Percent                              Weight %    Rare Earth Metal                                                                        Ethylene                                                                            Ethylene                                                                             Percent                                                                             HCl Conversion                                                                           Fluidization              Catalyst                                                                           KCl                                                                              CeCl.sub.3                                                                        to Alkali Metal                                                                         Conversion                                                                          Efficiency                                                                           EDC Yield                                                                           Actual                                                                             Corrected                                                                           of Catalyst               __________________________________________________________________________    Control                                                                            none                                                                             none                                                                              --        99.9  93.8   93.9  94.7 95.4  Fluid                     1    1.5                                                                              1.0 0.7       99.4  97.8   98.4  97.2 98.2  Slugging                  2    0.7                                                                              2.0 2.9       99.6  97.6   98.0  98.6 98.0  Fluid                     3    3.0                                                                              2.0 0.7       --    --     --    --   --    Severe slugging           4    2.5                                                                              2.5 1.0       --    --     --    --   --    Slugging & caking         5    0.5                                                                              3.0 6.0       99.6  97.8   98.2  97.3 98.1  Fluid                     6    1.5                                                                              4.0 2.7       99.2  97.5   98.3  96.3 97.8  Fluid                     7    1.5                                                                              5.0 3.3       99.5  98.2   98.7  97.0 98.6  Fluid                     8    2.0                                                                              5.0 2.5       99.7  97.9   98.2  97.6 98.6  Fluid                     9    3.0                                                                              5.0 1.7       99.5  97.5   98.0  95.7 98.1  Severe Slugging           10   5.0                                                                              5.0 1.0       --    --     --    --   --    Caking                    11   3.0                                                                              6.5 2.2       --    --     --    --   --    Hot spots and caking      12   1.0                                                                              7.0 7.0       99.8  98.1   98.4  98.3 98.6  Fluid                     13   3.0                                                                              8.0 2.7       --    --     --    --   --    Severe slugging &                                                             hot spots                 14   5.0                                                                              8.0 1.6       --    --     --    --   --    Severe slugging           15   1.0                                                                              10.0                                                                              10.0      99.0  97.7   98.7  97.5 98.0  Fluid                     16   5.0                                                                              10.0                                                                              2.0       97.2  96.6   99.4  96.5 96.9  Severe slugging           17   5.0                                                                              15.0                                                                              3.0       98.7  96.8   98.9  96.5 97.5  Hot spots &                                                                   slugging                  __________________________________________________________________________

The conditions of temperature and contact time (225°±1° C. and a contacttime of 22±0.4 seconds) were selected to yield comparative yet favorableresults. The HCl conversion was measured and then corrected to adjustfor any HCl feed variation from a theoretical 2:1 ratio over ethylene.The reactor design described in the specification was employed. Astandard oxychlorination catalyst consisting of cupric chloride on agamma alumina support was prepared and employed as the Control. Thefollowing data was obtained. Catalyst stickiness was also observed andreported.

The data shows that the use of a catalyst of cupric chloride, an alkalimetal, and a rare earth metal results in significantly higher % Ethyleneefficiency and % HCl conversion than the Control. However, as seen inExperiment 1 catalyst stickiness occurs unless the weight ratio of rareearth metal chloride to alkali metal chloride is at least 0.8 to 1.0 ormore. Experiments 3, 4, 9, 10, 11, 13, 14, 16 and 17 show that the useof a level of alkali metal of 2.5 percent or more by weight, no matterthat the weight ratio of rare earth metal chloride to alkali metalchloride is 0.8 to 1.0 or above, results in catalyst stickiness. Hence,both the weight ratio and an absolute weight level of alkali metal usedmust be controlled.

Experiments 2, 5, 6, 7, 8, 12, and 15 employ catalyst compositions ofthe present invention. In all cases, good fluidization of the catalystbed was obtained and maintained, and high percent ethylene efficiencyand high percent HCl conversion was achieved.

EXAMPLE I

The following series of experiments were performed to furtherdemonstrate the scope of the catalyst compositions of the presentinvention. All of the catalysts employed had a cupric chloride level of10.6% by weight along with the alkali metal salt (potassium chloride)and rare earth metal salt (cerium chloride). The catalysts were preparedand tested in the manner detailed in the Examples above using a molarratio of reactants of 1.0 ethylene/0.8 oxygen/2.0 HCl at a temperatureof 225°±1° C. at a contact time of 22±0.4 seconds. All of the catalystsexhibited good fluidization. The following results were obtained.

                                      TABLE I                                     __________________________________________________________________________                Weight Ratio of            Percent HCl                            Weight %    Rare Earth Metal                                                                       Percent Ethylene                                                                          Percent                                                                             Conversion                             Catalyst                                                                           KCl                                                                              CeCl.sub.3                                                                        to Alkali Metal                                                                        Conversion                                                                          Efficiency                                                                          EDC Yield                                                                           Actual                                                                            Corrected                          __________________________________________________________________________    1    0.5                                                                              3.0 6.0      99.6  97.8  98.2  97.3                                                                              98.1                               2    0.7                                                                              2.0 2.9      99.6  97.6  98.0  98.6                                                                              98.0                               3    1.0                                                                              1.0 1.0      99.6  97.8  98.2  97.3                                                                              98.3                               4    1.0                                                                              2.0 2.0      99.9  97.6  97.7  98.4                                                                              98.4                               5    1.5                                                                              4.0 2.7      99.2  97.5  98.3  96.3                                                                              97.8                               6    1.5                                                                              5.0 3.3      99.5  98.2  98.7  97.0                                                                              98.6                               7    1.0                                                                              7.0 7.0      99.8  98.1  98.4  98.3                                                                              98.6                               8    1.0                                                                              10.0                                                                              10.0     99.0  97.7  98.7  97.5                                                                              98.0                               9    2.0                                                                              5.0 2.5      99.1  97.4  98.3  96.4                                                                              97.8                               Control                                                                            none                                                                             none                                                                              --       99.9  93.8  93.9  94.7                                                                              95.4                               __________________________________________________________________________

EXAMPLE II

Another series of experiments were performed using a catalyst containing4 percent by weight of various rare earth metal salts in combinationwith 1.5 percent by weight of potassium chloride. The weight ratio ofrare earth metal chloride to alkali metal chloride is 2.7 to 1 in eachexperiment. Again, the catalysts were prepared and tested following theprocedures given in the above Examples. All of the catalysts exhibitedgood fluidization.

                                      TABLE II                                    __________________________________________________________________________                                    Percent HCl                                                 Percent Ethylene                                                                          Percent                                                                             Conversion                                    Catalyst                                                                           Rare Earth Metal                                                                       Conversion                                                                          Efficiency                                                                          EDC Yield                                                                           Actual                                                                            Corrected                                 __________________________________________________________________________    1    CeCl.sub.3                                                                             99.2  97.5  98.3  96.3                                                                              97.8                                      2    LaCl.sub.3                                                                             99.3  97.9  98.5  98.0                                                                              98.0                                      3    PrCl.sub.3                                                                             99.1  98.0  98.8  98.3                                                                              98.3                                      4    NdCl.sub.3                                                                             99.3  98.2  98.8  97.2                                                                              98.4                                      5    .sup.a RECl.sub.3                                                                      99.1  98.2  98.6  98.1                                                                              98.7                                      __________________________________________________________________________     .sup.a mixture of rare earth metals comprised of a majority of cerium and     lanthanum, with smaller amounts of neodymium and praeseodymium.          

EXAMPLE III

The following data shows that the catalyst compositions of the inventioncan be used over a wide range of operating conditions. At allconditions, good fluidization was obtained. The catalyst was preparedusing the procedure given in Example I. The catalyst contained 10.6weight percent cupric chloride, 1.5 weight percent potassium chloride,and 4.0 weight percent cerium chloride. Operating conditions and resultsare shown below.

                                      TABLE III                                   __________________________________________________________________________    Contact                          Percent HCl                                  Time Reaction  Percent Ethylene                                                                          Percent                                                                             Conversion                                   (seconds)                                                                          Temperature (°C.)                                                                Conversion                                                                          Efficiency                                                                          EDC Yield                                                                           Actual                                                                            Corrected                                __________________________________________________________________________    16.0 219       95.4  94.8  99.4  95.5                                                                              95.2                                          225       98.0  96.9  98.9  97.7                                                                              97.2                                          230       98.9  97.5  98.6  96.3                                                                              97.8                                     21.6 220       98.1  97.3  99.2  96.2                                                                              97.5                                          224       99.2  97.5  98.3  96.3                                                                              97.8                                          229       99.7  97.6  98.0  96.7                                                                              98.2                                     25.7 220       99.4  97.8  98.4  96.9                                                                              98.2                                          224       99.7  97.5  97.8  98.0                                                                              98.2                                          230       99.9  97.3  97.4  97.4                                                                              98.2                                     32.3 220       99.8  97.7  97.9  97.5                                                                              98.2                                          225       99.9  97.5  97.5  97.5                                                                              98.1                                          229       100.0 96.9  96.9  96.9                                                                              98.0                                     __________________________________________________________________________

Generally, as temperature and contact time increased, percent ethyleneconversion and efficiency increased. Percent HCl conversion (except atthe lowest operating conditions of 219° C. and 16 seconds contact time)remained fairly constant at a high level.

EXAMPLE IV

The experiments in Example III were essentially repeated using the samecatalysts as used in Example III. The following results were obtained.

                                      TABLE IV                                    __________________________________________________________________________    Contact                          Percent HCl                                  Time Reaction  Percent Ethylene                                                                          Percent                                                                             Conversion                                   (seconds)                                                                          Temperature (°C.)                                                                Conversion                                                                          Efficiency                                                                          EDC Yield                                                                           Actual                                                                            Corrected                                __________________________________________________________________________    4% LaCl.sub.3 and 1.5% KCl                                                    21.7 219       98.8  97.7  98.9  97.3                                                                              97.9                                          224       99.3  97.9  98.5  98.0                                                                              98.2                                          230       99.8  98.1  98.4  99.6                                                                              98.8                                     25.7 220       99.7  98.4  98.7  97.3                                                                              98.8                                          224       99.8  98.3  98.5  97.5                                                                              98.8                                          230       99.9  97.7  97.8  97.5                                                                              98.4                                     32.3 220       99.9  98.0  98.1  97.8                                                                              98.5                                          224       100.0 97.3  97.3  98.7                                                                              98.2                                          229       100.0 97.1  97.1  96.3                                                                              98.2                                     4% PrCl.sub.3 and 1.5% KCl                                                    21.0 220       99.3  98.2  98.8  97.1                                                                              98.7                                          225       99.1  98.0  98.8  98.3                                                                              98.3                                          230       99.8  98.1  98.3  97.5                                                                              98.9                                     24.8 220       99.6  97.9  98.3  98.4                                                                              98.4                                          225       99.8  97.4  97.6  98.8                                                                              98.2                                          230       99.9  98.0  98.1  97.5                                                                              99.0                                     31.8 220       100.0 97.4  97.4  97.8                                                                              98.1                                          225       100.0 97.6  97.6  97.6                                                                              98.4                                          230       100.0 96.3  96.3  97.2                                                                              98.1                                     4% NdCl.sub.3 and 1.5% KCl                                                    21.7 220       98.6  97.7  99.1  95.9                                                                              98.0                                          225       99.3  98.2  98.8  97.2                                                                              98.4                                          229       99.8  98.1  98.2  98.4                                                                              98.6                                     25.7 220       99.5  98.2  98.7  97.1                                                                              98.5                                          225       99.8  97.9  98.1  98.0                                                                              98.4                                          229       100.0 97.9  97.9  97.5                                                                              98.6                                     32.3 220       99.9  98.2  98.3  97.4                                                                              98.6                                          225       100.0 97.5  97.5  97.5                                                                              98.0                                          229       100.0 96.4  96.4  97.7                                                                              97.5                                     4% RECl.sub.3 and 1.5% KCl                                                    21.7 220       99.0  97.9  98.9  97.6                                                                              98.2                                          225       99.6  98.2  98.6  98.1                                                                              98.7                                          230       99.8  97.6  97.9  98.4                                                                              98.3                                     25.7 220       99.6  98.1  98.5  97.9                                                                              98.5                                          225       99.9  98.1  98.2  98.4                                                                              98.7                                          230       100.0 97.2  97.2  98.0                                                                              98.2                                     32.3 220       99.9  97.6  97.7  97.6                                                                              98.5                                          225       100.0 97.4  97.4  98.1                                                                              98.3                                          230       100.0 96.9  96.9  98.2                                                                              98.2                                     __________________________________________________________________________

We claim:
 1. A catalyst composition consisting essentially of afluidizable alumina support having a surface area of from about 80 toabout 200 m² /g having deposited thereon about 4% to 17% by weight of acopper salt, from about 0.25% to about 2.3% by weight of an alkali metalsalt(s), and from about 1% to about 10% by weight of a rare earth metalsalt(s) all weight percents calculated as the chloride salt and basedupon the total weight of the catalyst composition wherein the weightratio of the rare earth metal salt(s) to the alkali metal salt (s) is atleast 1:1 and wherein the alkali metal salt(s) and rare earth metalsalt(s) are not calcined to the support prior to depositing the coppersalt.
 2. The catalyst composition of claim 1 wherein the metals arecodeposited on a gamma alumnia support.
 3. The catalyst composition ofclaim 1 wherein the weight ratio of the rare earth metal salt(s) toalkali metal salt(s) is form one-to-one (1:1) to about thirty-to-one(30:1), and the salts are chloride salts.
 4. The catalyst composition ofclaim 3 wherein the alkali metal salt(s) is present in from about 0.5%to about 2.0% by weight, the rare earth metal salt(s) is present in fromabout 1% to about 10% by weight, the copper salt is copper chloride andis present in from about 8% to about 12% by weight, all weights basedupon the total weight of the catalyst composition, and the weight ratioof rare earth metal salt(s) to alkali metal salt(s) is from about 2:1 toabout 10:1.
 5. The catalyst composition of claim 4 wherein the alkalimetal is selected from the group consisting of potassium, lithium,sodium, rubidium, cesium and mixtures thereof.
 6. The catalystcomposition of claim 5 wherein the rare earth metal is selected from thegroup consisting of lanthanum, cerium, neodymium, praeseodymium andmixtures thereof.
 7. The catalyst composition of claim 6 wherein thealkali metal is potassium and the rare earth metal is cerium.
 8. Thecatalyst composition of claim 6 wherein the alkali metal is potassiumand the rare earth metal is neodymium.
 9. The catalyst composition ofclaim 6 wherein the alkali metal is potassium and the rare earth metalis lanthanum.
 10. The catalyst composition of claim 6 wherein the alkalimetal is potassium and the rare earth metal is praeseodymium.